“Floating screed” pavers are generally known to those skilled in the art and provide a method of coating an old or new roadway with a compacted layer of paving material, such as asphalt aggregate. “Floating screed” pavers typically include a tractor having a hopper at its front end for receiving paving material and a floating screed attached to its rear end. A conveyor system on the machine transfers the paving material from the hopper rearwardly for distribution in front of a floating screed.
The screed “floats” by virtue of being connected to the tractor by pivoted tow arms such that the screed physically levels any paving material lying higher than a predetermined height above the roadway surface. The tow arms of the screed are attached to the tractor at a “tow point.” In modern paver designs, the tow point can be moved vertically, typically via hydraulic cylinders, causing a corresponding movement in the leveling arms and screed. The configuration of the tow point connection between the tractor and screed can impact the degree to which the screed can “float.”
In the system of U.S. Pat. No. 8,747,022 B1 to Case, the paver includes a tow point assembly having a tow arm, a tow point plate, and a tow point support for securing to a traction unit. The rearward end of the tow arm is adapted for securing to a screed assembly, and the forward end of the tow arm is coupled to the tow point plate at a pivot point. The tow point plate is slidably disposed through an opening in the tow point support with the rollers of two coupled roller assemblies disposed to roll on the forward edges of the tow point support, and rollers of a third roller assembly disposed to roll on contact with rearward edges.